vaccines.gov

We performed a comprehensive analysis of vaccines.gov on 2026-07-02. The website returned an HTTP 200 status code with a server response time of 23320ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 43 KB. The website uses a secure HTTPS connection with a valid SSL certificate issued by Entrust Limited (OV type). The connection is encrypted using TLS 1.2 with the ECDHE-RSA-AES128-GCM-SHA256 cipher suite and sha256WithRSAEncryption signature algorithm. The certificate covers 28 domain(s) (Subject Alternative Names) and expires on 2027-01-07, which is 189 days from now. The security headers analysis reveals a score of 70/100 (good). The following security headers are properly configured: Content-Security-Policy, Strict-Transport-Security (HSTS), X-Frame-Options, and X-Content-Type-Options. However, the site is missing Referrer-Policy and Permissions-Policy, which could expose the site and its users to cross-site scripting (XSS), clickjacking, and other web-based attacks. Our technology detection scan identified 3 technologies across 3 categories powering vaccines.gov. The detected stack includes Next.js css, Webpack, and Google Analytics 4. The site uses Next.js as its primary framework (version css). Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, vaccines.gov receives an overall trust score of 84/100, classified as "Very Likely Safe".

After conducting a thorough safety and legitimacy analysis, vaccines.gov receives a trust score of 84/100, which places it in the "Very Likely Safe" category. This score is calculated by evaluating multiple factors including SSL certificate validity, domain registration history, email authentication protocols, security header configuration, and blacklist status across major threat intelligence databases. The analysis identified several positive trust signals: a valid HTTPS connection protecting data in transit, HSTS (HTTP Strict Transport Security) enforcement preventing protocol downgrade attacks, a valid SSL certificate issued by Entrust Limited with 189 days until expiration, SPF (Sender Policy Framework) email authentication preventing email spoofing, DMARC email authentication with a reject policy — the strongest available setting, and DNSSEC providing authenticated DNS responses. Areas of concern include: missing Referrer-Policy, potentially leaking URL information to third parties and the domain's WHOIS information is hidden behind a privacy service, making it harder to verify the owner's identity. While these issues don't necessarily indicate malicious intent, they represent areas where the website's security posture could be improved. We checked vaccines.gov against 8 major blacklist databases including Google Safe Browsing, Phishtank, Urlhaus, Openphish, Dnsfilter, Spamhaus Dbl, Surbl, and Virustotal. The domain passed all 8 checks with a clean status, meaning it has not been flagged for phishing, malware distribution, spam, or other malicious activities by any of the tested threat intelligence providers.

Our technology detection engine scanned vaccines.gov and identified 3 distinct technologies across 3 categories. This analysis is performed by examining HTTP response headers, HTML source code patterns, JavaScript library fingerprints, CSS framework signatures, and DNS records. Framework: Next.js (version css) — provides the application framework and routing for vaccines.gov. Build Tool: Webpack — bundles and optimizes the JavaScript and CSS assets for vaccines.gov. Analytics: Google Analytics 4 — tracks visitor behavior and provides traffic insights for vaccines.gov. We also extracted the following tracking identifiers: Google Analytics 4 Measurement ID G-SRP26B50XR. These IDs can be used to identify other websites operated by the same organization.

vaccines.gov delivers its homepage in 23320ms (server response time), which is considered slow by industry standards. The total page weight is 43 KB, and we detected 40 resource requests loading assets from 3 third-party domains. A high number of third-party domains can significantly impact page load time due to additional DNS lookups and TLS handshakes required for each domain. The website uses Gzip compression for text-based assets, achieving an estimated 60.0% reduction in transfer size. This reduces bandwidth usage and improves page load times, especially for visitors on slower connections. Asset minification status: 0 out of 2 CSS files and 0 out of 24 JavaScript files are minified. Minifying the remaining 26 unminified file(s) could further reduce page weight by 10-30% for those assets. Minification is a best practice that reduces download sizes without affecting functionality. From an environmental perspective, each page view of vaccines.gov produces approximately 0.02g of CO₂, earning a carbon rating of A. This places the website among the cleanest on the web, demonstrating efficient use of server resources and optimized content delivery. For reference, the average web page produces about 0.5g of CO₂ per page view. The page weight of 43 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for vaccines.gov. This typically means the site doesn't have enough real-world Chrome user traffic to generate statistically significant field data, or the domain is not included in the CrUX dataset. Core Web Vitals (LCP, INP, CLS) are important Google ranking factors that measure real user experience.

vaccines.gov resolves to the IPv4 address 198.246.102.49, but does not support IPv6. IPv6 adoption is increasingly important as IPv4 address space becomes exhausted, and some ISPs and regions are transitioning to IPv6-only connectivity. The domain has 1 A record(s) configured. The domain name system is managed by 6 name servers: a1-168.akam.net, a11-67.akam.net, a20-65.akam.net, a24-65.akam.net, a3-67.akam.net, and a8-64.akam.net. Having 6 name servers provides good redundancy — if one fails, the others can continue serving DNS queries. The choice of name servers often indicates the DNS hosting provider or CDN service being used. SPF (Sender Policy Framework) is configured, which specifies which mail servers are authorized to send email on behalf of this domain. This helps prevent email spoofing and improves email deliverability. DMARC (Domain-based Message Authentication, Reporting and Conformance) is configured with a reject policy — the strongest setting, instructing receiving servers to reject unauthorized emails entirely. DKIM was not detected. Without DKIM, recipients cannot cryptographically verify that emails claiming to be from this domain are authentic. DNSSEC is enabled for vaccines.gov, providing an additional layer of security by cryptographically signing DNS records. This prevents DNS cache poisoning and man-in-the-middle attacks that could redirect visitors to malicious websites.

The homepage of vaccines.gov contains 94 words of visible text content. This is a relatively short page — adding more descriptive content could improve search engine visibility. The page is structured with 0 H2 headings, 1 H3 headings, 0 H4 headings. The page includes 3 images. All images have proper alt text attributes ✓, which is excellent for both accessibility (screen readers) and SEO (search engines can understand image content). The link structure consists of 2 internal links pointing to other pages on the same domain and 5 external links pointing to third-party websites. There are 24 external JavaScript files, 2 CSS stylesheets, and 0 iframes on the page. Notable missing features: XML Sitemap, robots.txt, and Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility.

The title tag for vaccines.gov is good at 24 characters: "Find pharmacies near you". The length is acceptable, though it may be slightly truncated in some search result displays. The meta description is 67 characters (acceptable): "Vaccines.gov helps you find nearby pharmacies in the United States.". Google typically displays up to 155-160 characters of the meta description in search results. A compelling meta description with a clear call-to-action can significantly improve click-through rates from search results. A favicon is configured. Open Graph meta tags are configured with 3/4 recommended fields: OG title ("Find pharmacies near you..."), OG description, OG image (social sharing thumbnail), These tags control how the page appears when shared on Facebook, LinkedIn, and other social media platforms that support the Open Graph protocol. A Twitter Card of type summary_large_image is configured, which controls how links appear when shared on Twitter/X. The "summary_large_image" type displays a large image preview, which typically generates higher engagement rates than the basic card type.